Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751551AbWBVWfM (ORCPT ); Wed, 22 Feb 2006 17:35:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751570AbWBVWfM (ORCPT ); Wed, 22 Feb 2006 17:35:12 -0500 Received: from omx1-ext.sgi.com ([192.48.179.11]:34281 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S1751551AbWBVWfK (ORCPT ); Wed, 22 Feb 2006 17:35:10 -0500 Date: Wed, 22 Feb 2006 14:34:48 -0800 (PST) From: Christoph Lameter To: akpm@osdl.org cc: alokk@calsoftinc.com, manfred@colorfullife.com, Pekka Enberg , linux-kernel@vger.kernel.org Subject: slab: Remove SLAB_NO_REAP option Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4935 Lines: 115 SLAB_NO_REAP is documented as an option that will cause this slab not to be reaped under memory pressure. However, that is not what happens. The only thing that SLAB_NO_REAP controls at the moment is the reclaim of the unused slab elements that were allocated in batch in cache_reap(). Cache_reap() is run every few seconds independently of memory pressure. Could we remove the whole thing? Its only used by three slabs anyways and I cannot find a reason for having this option. There is an additional problem with SLAB_NO_REAP. If set then the recovery of objects from alien caches is switched off. Objects not freed on the same node where they were initially allocated will only be reused if a certain amount of objects accumulates from one alien node (not very likely) or if the cache is explicitly shrunk. (Strangely __cache_shrink does not check for SLAB_NO_REAP) Getting rid of SLAB_NO_REAP fixes the problems with alien cache freeing. Signed-off-by: Christoph Lameter Index: linux-2.6.16-rc4/mm/slab.c =================================================================== --- linux-2.6.16-rc4.orig/mm/slab.c 2006-02-17 14:23:45.000000000 -0800 +++ linux-2.6.16-rc4/mm/slab.c 2006-02-22 14:06:23.000000000 -0800 @@ -170,12 +170,12 @@ #if DEBUG # define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \ SLAB_POISON | SLAB_HWCACHE_ALIGN | \ - SLAB_NO_REAP | SLAB_CACHE_DMA | \ + SLAB_CACHE_DMA | \ SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \ SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ SLAB_DESTROY_BY_RCU) #else -# define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \ +# define CREATE_MASK (SLAB_HWCACHE_ALIGN | \ SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \ SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ SLAB_DESTROY_BY_RCU) @@ -642,7 +642,7 @@ static struct kmem_cache cache_cache = { .limit = BOOT_CPUCACHE_ENTRIES, .shared = 1, .buffer_size = sizeof(struct kmem_cache), - .flags = SLAB_NO_REAP, + .flags = 0, .spinlock = SPIN_LOCK_UNLOCKED, .name = "kmem_cache", #if DEBUG @@ -1689,9 +1689,6 @@ static inline size_t calculate_slab_orde * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check * for buffer overruns. * - * %SLAB_NO_REAP - Don't automatically reap this cache when we're under - * memory pressure. - * * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware * cacheline. This can be beneficial if you're counting cycles as closely * as davem. @@ -3487,10 +3484,6 @@ static void cache_reap(void *unused) struct slab *slabp; searchp = list_entry(walk, struct kmem_cache, next); - - if (searchp->flags & SLAB_NO_REAP) - goto next; - check_irq_on(); l3 = searchp->nodelists[numa_node_id()]; Index: linux-2.6.16-rc4/include/linux/slab.h =================================================================== --- linux-2.6.16-rc4.orig/include/linux/slab.h 2006-02-17 14:23:45.000000000 -0800 +++ linux-2.6.16-rc4/include/linux/slab.h 2006-02-22 14:05:25.000000000 -0800 @@ -38,7 +38,6 @@ typedef struct kmem_cache kmem_cache_t; #define SLAB_DEBUG_INITIAL 0x00000200UL /* Call constructor (as verifier) */ #define SLAB_RED_ZONE 0x00000400UL /* Red zone objs in a cache */ #define SLAB_POISON 0x00000800UL /* Poison objects */ -#define SLAB_NO_REAP 0x00001000UL /* never reap from the cache */ #define SLAB_HWCACHE_ALIGN 0x00002000UL /* align objs on a h/w cache lines */ #define SLAB_CACHE_DMA 0x00004000UL /* use GFP_DMA memory */ #define SLAB_MUST_HWCACHE_ALIGN 0x00008000UL /* force alignment */ Index: linux-2.6.16-rc4/drivers/scsi/iscsi_tcp.c =================================================================== --- linux-2.6.16-rc4.orig/drivers/scsi/iscsi_tcp.c 2006-02-17 14:23:45.000000000 -0800 +++ linux-2.6.16-rc4/drivers/scsi/iscsi_tcp.c 2006-02-22 14:08:46.000000000 -0800 @@ -3639,7 +3639,7 @@ iscsi_tcp_init(void) taskcache = kmem_cache_create("iscsi_taskcache", sizeof(struct iscsi_data_task), 0, - SLAB_HWCACHE_ALIGN | SLAB_NO_REAP, NULL, NULL); + SLAB_HWCACHE_ALIGN, NULL, NULL); if (!taskcache) return -ENOMEM; Index: linux-2.6.16-rc4/fs/ocfs2/super.c =================================================================== --- linux-2.6.16-rc4.orig/fs/ocfs2/super.c 2006-02-17 14:23:45.000000000 -0800 +++ linux-2.6.16-rc4/fs/ocfs2/super.c 2006-02-22 14:08:17.000000000 -0800 @@ -959,7 +959,7 @@ static int ocfs2_initialize_mem_caches(v ocfs2_lock_cache = kmem_cache_create("ocfs2_lock", sizeof(struct ocfs2_journal_lock), 0, - SLAB_NO_REAP|SLAB_HWCACHE_ALIGN, + SLAB_HWCACHE_ALIGN, NULL, NULL); if (!ocfs2_lock_cache) return -ENOMEM; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/